1. Field of the Invention
The invention relates generally to arc lamps, and specifically to components and methods used to reduce the cost of manufacturing xenon arc lamps.
2. Description of the Prior Art
Short arc lamps provide intense point sources of light that allow light collection in reflectors for applications in medical endoscopes, instrumentation and video projection. Also, short arc lamps are used in industrial endoscopes, for example in the inspection of jet engine interiors. More recent applications have been in color television receiver projection systems.
A typical short arc lamp comprises an anode and a sharp-tipped cathode positioned along the longitudinal axis of a cylindrical, sealed concave chamber that contains xenon gas pressurized to several atmospheres. U.S. Pat. No. 5,721,465, issued Feb. 24, 1998, to Roy D. Roberts, describes such a typical short-arc lamp. A typical xenon arc lamp, such as the CERMAX marketed by ILC Technology (Sunnyvale, Calif.) has a three-legged strut system that holds the cathode electrode concentric to the lamp's axis and in opposition to the anode.
The manufacture of high power xenon arc lamps involves the use of expensive and exotic materials and sophisticated fabrication, welding, and brazing procedures. Because of the large numbers of xenon arc lamps being produced and marketed, every opportunity to save money on the materials and/or assembly procedures is constantly being sought. Being the low-cost producer in a market always translates into a strategic competitive advantage.
For example, the CERMAX-type arc lamp 100 shown in FIG. 1 and sold in the commercial market can easily require as much as forty-eight percent in material costs and fifty-two percent in labor costs. The total manufacturing cost acts to set the minimum amount that can be charged at retail. The supply-versus-demand rule therefore tends to limit the production volumes that can be sold because of the high price points that must be charged. The lamp 100 is conventional and comprises an optical coating 102 on a sapphire window 104, a window shell flange 106, a body sleeve 108, a pair of flanges 110 and 112, a three-piece strut assembly 114, a two percent thoria cathode 116, an alumina-ceramic elliptical reflector 118, a metal shell 120, a copper anode base 122, a base support ring 124, a tungsten anode 126, a gas tubulation 128, and a charge of xenon gas 130. All of which are brazed together in a complex assembly process. Fewer parts, less expensive materials, simpler tooling, and fewer assembly steps would all help to reduce the costs of making such CERMAX-type arc lamps.